The major goal of this research project is to examine pharmacologic interactions of adrenergic and cholinergic nervous systems in cat and monkey eyes. Changes in pupil size, intraocular pressure and aqueous humor dynamics in response to agents affecting norepinephrine and acetylcholine receptors and metabolism at specific sites will first be determined. The effectiveness of these agents after the pharmacologic production of adrenergic or cholinergic supersensitivity and subsensitivity will then be examined. Involvement of cyclic AMP as a mediator will be assessed by parallel measurement of this nucleotide in aqueous humor. Basic mechanisms underlying the production of supersensitivity and subsensitivity in the isolated iris sphincter and dilator will finally be explored.